1. Field of the Invention
The invention relates to configuring the leads of integrated circuit (IC) chips which are used in conjunction with printed circuit boards (PCBs). More particularly, the invention relates to a method and apparatus for bending and/or straightening the leads of fine pitch components which have been damaged.
2. Description of the Related Technology
In the surface mount board manufacturing industry, high speed automated placement machines are used to place surface mount components onto bare PCBs. To accomplish this process, parts are first received from a manufacturer in one of several mediums, including 1) loose parts in a tube; 2) parts in a tape and reel; and 3) parts trays. These parts are extracted from their packaging mediums and then loaded into a placement machine which automatically places them onto the PCB. Prior to placement, the leads of each part are inspected by a machine vision system of the placement machine.
Typical machine vision systems have a back-lighting system, which shines light on a component or part, and a camera which views the illuminated component from a bottom perspective of the component. The light and the component produce a grey-scale image as a result of the shadows produced by the component. This grey-scale image is translated into black or white pixels within the camera. If a lead of the component, is bent or damaged, improper pixels will either be black or white which is detected by the machine vision system. The configuration of black and white pixels produced by an undamaged component is stored within a memory of the machine vision system. The pixel configuration produced by a component being inspected is compared to this "true" pixel configuration and if a mismatch occurs, the component is designated as not passing the visual inspection and is rejected by the automatic placement machine. Of course, machine errors can also cause a component to be rejected. Such automated placement machines, as well as their vision systems, are well-known in the art.
If a part passes the inspection, placement coordinates are calculated, and the part is then placed onto the PCB. If a part is rejected, it is typically taken out of the machine manually and placed into a medium with other damaged parts. During their loading and unloading from the automatic placement machine, parts can be easily damaged. This is particularly true of fine pitch components whose leads are extremely thin and frail, sometimes being less than 20 mils thick. The machine vision system will not allow the machine to place these damaged parts.
Referring to FIG. 1, a typical fine pitch integrated circuit (IC) 11 is shown. The IC 11 includes multiple fine pitch leads 13 extending outwardly from each side surface 15 of the IC body 17. As the industry is moving toward the integration of more and more components into an IC package, it is moving toward finer pitch packages having pin counts of 100 or more. With the trend toward larger pin count packages, lead pitches have decreased in order to preserve real estate efficiency on a printed circuit board (PCB). With the increase in usage of application specific integrated circuit (ASIC) devices, for example, finer pitch devices have become very common.
As mentioned above, one inherent disadvantage of using fine pitch components is the increased delicacy with which these components must be handled. Because they are so fragile, the leads of these components are easily bent or otherwise damaged during the assembly process.
Prior art methods for repairing damaged fine pitch leads typically involve a human operator who manually attempts to bend the leads back into proper alignment using tweezers or some other tool. This process is tedious, time-consuming and inaccurate. Often, if a large number of fine pitch leads have been damaged, the component is discarded or destroyed. The destruction of these fine pitch parts can be very costly to the manufacturer, since fine pitch components may be worth hundreds or even thousands of dollars each. When high numbers of components are damaged through shipping, manufacturing, or mishandling, a sizable amount of profit can be destroyed. Therefore, a fast and accurate method and apparatus for configuring and/or repairing the leads of damaged fine pitch components is needed.